Despite the availability of many agents for the management of type 2 diabetes mellitus (T2DM), the majority of patients with T2DM have hemoglobin A1c (HbA1c) levels above target. The American Diabetes Association (ADA) has recently published consensus guidelines for T2DM management recommending the simultaneous introduction of lifestyle changes and metformin at the time of diagnosis, a narrow range of medication classes (metformin, sulfonylurea, glitazones, insulin), and medication changes no less frequently than every 3 months. This consensus algorithm has not been validated previously, and most often T2DM care is guided by clinical judgement. Patients with T2DM, including those who are not treated with medications, have been identified in a database of primary care practices. We propose first an epidemiologic study to identify factors associated with metformin treatment as initial therapy for T2DM and secondly a randomized clinical trial in which untreated patients will be randomized into either a metformin arm or a usual diabetes care arm, in order to evaluate metformin's effectiveness in achieving glycemic targets and also to identify factors limiting widespread metformin use in general practice. [unreadable] [unreadable] Specific Aim 1: To determine whether patients with T2DM in primary care practices who are currently not treated with metformin differ from those who are treated with metformin using easily ascertainable demographic and clinical data derived from a large patient registry and an electronic medical record. This research will identify barriers to metformin use and craft subsequent strategies to improve implementation of the consensus algorithm. As a secondary aim, in a longitudinal analysis of the database, we will identify factors associated with T2DM progression over a 1-year period in subjects initially well controlled (HbA1c<7) [unreadable] on metformin. [unreadable] [unreadable] Specific Aim 2: To evaluate if early initiation of metformin in subjects with T2DM and HbA1c <7 maintains [unreadable] target metabolic control better than usual care in a randomized controlled trial. As a secondary aim, we will [unreadable] evaluate factors that limit metformin initiation in patients with no contraindication to metformin use. [unreadable] Lay Statement: [unreadable] [unreadable] T2DM is a significant public health problem, with serious complications often related to poor glucose [unreadable] (sugar) control. We will examine the first step of diabetes treatment according to new treatment guidelines to [unreadable] determine if they are effective in improving glucose levels in patients with T2DM. Improving glucose control [unreadable] is extremely important in order to improve the long-term health of the 20 million people with T2DM in the US. [unreadable] [unreadable] [unreadable] [unreadable]